Plug for low temperature storage containers



Dec. 18, 1962 w. HAUMANN 3,069,044

PLUG FOR LOW TEMPERATURE STORAGE CONTAINERS Filed Dec. 5, 1960 2 Sheets-Sheet 1 /J 1/ A6 1y I 9 I I 4 INVENTOR. WILFRIED HAUMANN waw% ATTORNEY Dec. 18, 1962 w. HAUMANN 3,069,044

PLUG FOR LOW TEMPERATURE STORAGE CONTAINERS Filed 1960 2 Sheets-Sheet 2 I 7 l l I A \1 V 1 ,u {H I /a a; A

7 I i i /a- 4 f -4 j 8 (W Z.

Z --gJNd p A d [/7 1/1 60 9 J 3. 3 j A .9

7 3 II I [In I A n fi i E? r INVENTOR. Z4

WILFRIED HAUMANN V ATTORNEY United States Patent Ofiice 3,069,044 Patented Dec. 18, 1962 3,069,044 PLUG FOR LOW TEMPERATURE STORAGE CONTAINERS Wilfried Haumann, Indianapolis, Ind., assignor to Union Carbide Corporation, a corporation of New York Filed Dec. 5, 1%0, Ser. No. 73,598 .4 Claims. (Cl. 220-14) The present invention relates to low temperature storage containers and particularly to a plug adapted to be co-operatively received in the access port of such a container.

Containers of the type hereindescribed may be used for storing materials at extremely low temperatures, which materials are maintained in a refrigerated state until such time as they are required for use. A typical container of the type presently contemplated is used for refrigerating biologicals and bovine semen which are preferably stored at a temperature approximating that of liquid nitrogen. Many such containers have been developed which embody sufiicient insulating characteristics to maintain the contained products at a reduced temperature. In the majority of such containers, a single port, generally in the top portion, provides the only means of access to the container interior. Normally, the container access opening is provided with a low thermally conductive plug in order to lessen the amount of heat leak into the cold storage area, which heat would, of course, reduce overall refrigerating capacity. 1 A plug of the type referred to is generally elongated and slideably received in the container access port in such a manner as to permit easy removal. An ever present problem associated with a container having a plug of this nature, is that when the plug is withdrawn from the port, pumping action will cause the refrigerant vapors contained within the container to mix with the warmer, moist, surrounding atmosphere, thus freezing the moisture to form ice which will deposit on the mouth of the container and thus provoke handling difiiculties. Also, after being removed, the plug will tend to warm up in the outside air and consequently will require cooling down when replaced in the container opening. (A further detrimental effect resulting from the intermixing of warm atmospheric air with the refrigerated atmosphere, is that a vaporous fog will be created within the access passage and thereby hamper visibility into the container storage area.

It is therefore an object of the present invention to provide a plug for use in the access port of a low temperature container.

A further object is to provide such a plug which will permit access to the container interior with a minimum amount of heat leak to the refrigerated storage area.

Another object is to provide a low temperature container plug which precludes the necessity of removal thereof when access to the container is desired.

In the drawings:

FIG. 1 is a vertical elevation of an embodiment of the presently disclosed plug shown in partial cross-section;

FIG. 2 is an enlarged segmentary view in cross-section of a portion of the plug shown in FIG. 1;

FIG. 3 is another enlarged segmentary view in crosssection of the lower portion of the plug; and

FIG. 4 is a top view of the plug.

In brief, the present invention contemplates a plug adapted'to co-operatively engage the cylindrical access opening of a low temperature container for providing a closure thereto. The plug comprises essentially an elongated casing having cylindrical side walls and a base plate, including an aperture in the latter. A closure plate fixed to the casing upper edge is also provided with an aperture to allow access to the container interior. A rotatable shaft extending substantially axially through the cup is terminally journalled to the base plate and top closure respectively, the upper portion of said shaft extending beyond said closure to be actuated outside the container. A plurality of vertically spaced baflies, disposed perpendicular to the casing central axis, are peripherally engaged with the cylindrical wall to define adjacent compartments within the cup. Openings in each of said bafiies are in substantially vertical alignment with each other and with said base opening and top aperture to provide a passage through the plug. Vertically spaced vanes engaging the rotatable shaft and extending across the diameter of the cup are disposed to extend between each adjacent pair of baffies, and are horizontally rotatable inthe cup in response to rotation of the shaft. A portion of each vane is removed to constitute a vertical passage when the openings of said baflles and said vanes are brought into alignment. A cover plate, upwardly adjacent the top plate, engages the shaft to be rotated therewith, said cover plate having an opening which may be vertically aligned with the bottom closure aperture.

Referring to FIG. 1 a specific embodiment of the low temperature plug is designated at 10 and includes an elongated casing or closed ended cup having cylindrical side walls defined by a tubular member 13, with a partition 14 fixed to the lower edge thereof. An aperture 15 in said partition provides access to the interior of the cup. The plug is normally received in the neck tube opening of a low temperature storage container such that the outer walls thereof may be disposed proximately close to the adjacent neck tube, preferably defining a slight annular space therebetween. Such space will allow refrigerant vapors to pass upwardly around the tube and mix with any incoming atmosphere, thus preventing loss of refrigeration.

To minimize the amount of heat which will normally be conducted to the container interior, the plug is fabricated of a material having poor thermally conductive characteristics. For example, the elongated member 13 may be a thin walled tube of Micarta or a similar thermosetting plastic material. In that the refrigerant used in the container may be a liquefied gas such as oxygen or nitrogen, the material of which the plug is formed must be sufliciently resistant to embrittlement temperatures on the order of K. to properly withstand such low temperature and remain operative.

The top closure 16, as shown in FIGS. 1 and 2, consists of a thin metallic plate, positioned to the upper edge of tube 13'. The peripheral edge of said plate may be turned in a downward direction as shown in order to engage and be supported by the container upper edge when the plug is properly received therein. An opening 17, similar to the aperture provided in the lower panel 14, is vertically positioned such that said aperture and opening respectively are substantially aligned one above the other.

An elongated rotatable shaft 18, extending axially through the plug, is terminally journalled at the panel 14 and top closure 16 respectively. As seen in the enlarged FIGURE 3, the shaft comprises preferably a thin-walled tube of a low thermally conductive metal such as stainless steel. A center tapped, stepped insert 20, fixed to the tube lower end, co-operates with a removable washer 22 to constitute the lower shaft bearing surface. Again referring to FIG. 3, a machine screw 24 or similar fastening means fixedly maintains said parts in relation to the lower panel14. The shaft bearing means here shown is not considered to be unique and may be replaced by any suitable combination of elements for permitting rotationof the center shaft.

Referring to FIG. 2, the upper portion of shaft 18 is provided with a bearing insert 26 which may be welded into the shaft end. A stepped portion 30 of the insert defines a circumferential shoulder which registers with an opening in the top closure 16 and is laterally retained by a sleeve bearing 32, thereby permitting rotative movement of the shaft about its center axis. A short extension 34 protruding beyond the plug upper surface may be engaged by a handle or a similar actuating device external of the storage container for rotation of the shaft 18. For instance, as shown in FIG. 1, an elongated handle 36 may be fixed to the extension 34 by a pin 38 transversing both of said members to hold said members in fixed relationship.

With reference to FIGS. 1 and 2, a cover plate 40 upwardly spaced from the top closure 16 is associated with shaft 18 to be responsive to rotative actuation by the handle 36. An opening 41 formed in said plate is positioned vertically opposite that of openings 17, and the aperture 15 in panel 14, so that rotation of the shaft will bring all three openings into vertical alignment. By such means, the access passage to the container interior may be effectively covered or exposed as required to either close the container from the atmosphere or to permit transfer of the refrigerated materials to and from the storage area.

The plug interior is compartmented by a plurality of vertically disposed stationary bafiies 39, 42, 44, 46 and 48 having the peripheral edges thereof engaged to the inner wall of tube 13. An opening in each of said baffles is disposed in vertical alignment with the opening in the lower panel 14. The bafifes may be further supported by slideably registering in accomodating slots formed into center shaft 18.

As illustrated in FIG. 1, intermediate each adjacent pair of stationary baffies, there is interposed a flat, horizcntally rotatable vane, i.e., 50, 52, 54', 56 and 58, transversing substantially the plug diameter and being engaged to the shaft 18 to be rotated therewith. A part of each of said vanes is removed corresponding to the openings in the stationary bafiie plates such that upon proper alignment, a longitudinal passage is defined to permit access to the container interior while the plug remains positioned in the container access opening.

Sealing means 60 and 60a such as an elongated strip, extend diametrically through shaft 18 and across the tube 13. Sealing means 69 prevents the passage of refrigerant vapors up through the cup between the adjacent baffies, while sealing means 60a prevents the prevents the passage of atmospheric air.

It has been found that under operating conditions the presently disclosed plug will effectively reduce heat leak to the container storage area and still allow ample access thereto for transfer of refrigerated materials. The respective baffles and vanes may be fabricated of a thin gage material such as copper or aluminum, which, if provided with a polished surface, are found to have a high degree of surface emissivity which will reduce heat leak through radiation. It may be seen that the space between each pair of adjacent bafiies and vanes constitutes a barrier to the uninterrupted passage of heat into the refrigerated container interior. These tiered compartments effectively limit the free flow of air and consequently the passage of heat through the plug. While according to FIG. 1, the baffles and vanes are shown as being rather equally spaced, this is not an essential requirement since optimum spacing would have to be determined for a given temperature gradient within the container neck tube for the desired suppression of convection currents between the baflies and vanes.

In the preferred form of the invention, as depicted in FIG. 1, the openings in the baffies and the removed portion of the vanes are such that the baffies and vanes will assume a generally semi-circular configuration. Such a construction will provide an access passage to the container storage area which is about 'half the size of the container access opening.

To be properly utilized, the plug is fully inserted into a storage container neck tube and supportably retained therein against the laterally protruding down curved edge of the top closure. By rotating the center shaft, the respective baffies and vanes may be displaced from alignment to define a plurality of vertically spaced, parallel compartments along the axis of the plug. When positioned in such manner, the cover plate 49 is aligned so as to prevent air flow into the plug interior and thus minimize heat flow thereto. In order to transfer materials either to or from the container refrigerated storage area, the shaft may be sufficiently rotated to align the opening 41 of cover 40, and the vertically spaced openings or cut-out segments of the bafiies and the vanes, with the aperture 15 of panel 14 and aperture 17 of closure 16 thereby providing the access opening to the container interior through which said materials may be transferred. is is readily seen that by keeping the plug in place during such transfer, there is relatively no pumping action and mixing of the moist atmosphere and refrigerant vapors. Thus there will be relatively no fogging of the container opening nor will there be any warming of the container plug.

What is claimed is:

1. In a low temperature storage container having a cylindrical top opening affording access to the storage area, a plug supportably received in said top opening providing a low thermally conductive closure thereto, said plug comprising: an elongated cylindrical casing having the outer wall thereof disposed adjacent the wall of said top opening, a plate fixed to each end of said casin g defining a chamber therein, a rotatable shaft axially transversing said casing and being terminally journalled at each of said end plates, a portion of said shaft extending beyond the upper of said plates to be rotatably actuated external to the container, longitudinally spaced battles disposed substantially perpendicular to the casing axis and fixedly secured to said casing inner wall to define a plurality of compartments, vertically spaced vanes fixedly secured to said shaft to be rotated thereby into said respective compartments, said baffles and vanes adapted to be aligned upon rotation of said shaft to define a vertical passage providing access to the storage area, said passage being closed by further rotation of the shaft, and means for supportably positioning said plug in relation to said top opening.

2. A neck plug substantially as described in claim 1 in which the respective baffles and vanes constitute a substantially semi-circular plate, said vanes being spaced along said shaft so that at least one thereof is rotated into each of said compartments upon rotation of the shaft.

3. In a low temperature storage container having a cylindrical top opening affording access to the storage area, a plug axially received in said opening providing a low thermally conductive closure thereto, said plug comprising: an elongated cylindrical casing slideably received in said opening, a plate fixed to each end of said casing defining a chamber therein, a plurality of axially spaced bafifes disposed in said casing substantially perpendicular to the central axis of said casing, said baffies peripherally fixed to the casing inner wall to define a plurality of adjacent compartments therebetween, a rotatable shaft extending substantially coaxial with the casing axis, said shaft being journalled in said respective end plates, an upper portion of said shaft protruding from the top surface of said plug to be actuated thereby external to the container, and spaced vanes fixed to said shaft to be rotatable in a plane substantially perpendicular to said axis, at least one of said vanes disposed intermediate each adjacent pair of said baffles, said baffies and vanes adapted to be positioned by rotation of said shaft to define a vertical passage through said plug thereby providing access to the container storage area.

4. In a low temperature storage container having an upright elongated neck tube in the top portion thereof communicating with the storage area, a low thermally conductive plug supportably received in said neck tube providing a closure thereto and adapted to permit access to said storage area with said plug so received, said plug comprising: an elongated casing having opposed upper and lower ends, said casing disposed substantially coaxial with said neck tube and in slideable relation therewith, a base plate fixed to the casing lower end providing a closure thereto, an aperture in said base plate, a second plate fixed to the casing upper end, having an opening therethrough in substantial alignment with the aperture in said base plate, a rotatable shaft extending coaxial of said casing, said shaft being terminally journalled to said base plate and second plate respectively, a portion of said shaft transversing said second plate to be rotatably actuated external to the container, a plurality of longitudinally spaced bafiles positioned substantially perpendicular to the casing axis and peripherally engaging the inner wall thereof to define a compartment intermediate each adjacent pair of baflies, an aperture in each of said battles in vertical alignment with each other and with the apertures in said base plate, vertically spaced vanes engaging said shaft and disposed to be horizontally rotated in said casing in response to rotation of the shaft, an aperture in each of said vanes in vertical alignment with each other and with the respective aperture in said base plate when said vanes are rotatably positioned between said bafiies, a cover plate upwardly spaced from and immediately adjacent said second plate and engaging said shaft to be rotated thereby, an opening provided in said cover plate in substantial alignment with said aperture in said vanes whereby said respective vanes and cover plate may be rotated into alignment with said baffles thereby defining a vertical passage longitudinally transversing said plug and providing access to the container storage area, which passage may be thereafter closed by further rotation of the shaft to misalign the respective apertures.

References Cited in the file of this patent UNITED STATES PATENTS 432,474 Brinkop' July 15, 1890 923,895 Ryburg et a1. June 8, 1909 FOREIGN PATENTS 470,229 France June 10, 1914 

